Several of the Swampies pursuing the Doctor & Romana are seized by Kroll and the rest flee. Thawn plans to use the next orbit shot from the refinery to attack Kroll, and destroy the Swampies in one go. The Doctor & Romana return to the refinery and witness Dugeen standing up to Thawn's plans. He forces Fenner to cooperate at gunpoint, but the Doctor sneaks into the rocket silo to sabotages the launch. The wounded Dugeen tries to about the launch but is killed by Thawn. The Doctor's sabotage halts launch with 3 seconds to go as Kroll submerges. Thawn goes to check the ignition and catches The Doctor & Romana leaving the rocket launching chamber. The Swampies invade the refinery. As Thawn returns to the control room with the Doctor & Romana, Fenner detects Kroll approaching the refinery. The Swampies enter, slaying Thawn, as Kroll attacks the refinery. The Doctor has Fenner operate the base centrifuge, the noise of which drives Kroll away. The Swampie leader Ranquin believes that Kroll has heard his prayers but his followers realise it was the machinery. Ranquin is taken by Kroll. The Doctor tests his theory and touches Kroll with the tracer, transforming it into the fifth segment of the Key To Time. Fenner realises the rocket firing bay is blocked, but the computer is trying to run the next launch sequence. The Doctor sabotages the computer deactivating the launch sequence. They leave Fenner behind awaiting a pick up from the authorities. The Doctor explains how Kroll consumed the High Priest's object of power, the fifth segment, and used it to grow to giant size.

You know what? Apart from the obvious bit of padding at the end - we've defeated the monster but suddenly the computer wants to launch the rocket automatically and we must stop it - that wasn't a bad episode. It timed at just over 21 minutes so was under running a tad even with the padding added on but there was some action in it, we got to do something with the series story for the quest for the Key to Time and we got some of the message behind the story coming through with Thawn racist attitude to the Swampies.

The first and last episodes of Power of Kroll aren't too bad. The middle two are awful. Blame for the story is usually laid at the door of Director Norman Stewart, especially since he also directed the #1 Turkey from the previous season, Underworld. But I'm not sure it's his fault at all: he makes great use of the location and the model work isn't bad either. Neither does writer Robert Holmes have to shoulder the blame as there is some good stuff going on here with an underlying anti-racism message. I know the script was written in a hurry to cover a script that fell through and perhaps, like Seeds of Doom, it could have done with another pass or two before reaching the screen. Holmes takes leave of the show for a while following this story, but he'll be back in a few years time.

Power of Kroll was novelised by Terrance Dicks. It was released on video in June 1995 on the same day as the following story, the Armageddon Factor, to form the final pair of stories from the Key to Time season released, with The Ribos Operation & The Pirate Planet coming out in April of the year and followed by Stones of Blood & Androids of Tara in May. The Key To Time season was a set of releases which came with a specially designed spine picture that ran over all six title. While there has never been a video boxset release of the Key To Time, it's only ever been available as a boxset on DVD. In October 2002 all six Key To Time stories were released in Region 1 with minimal extras & restoration to help satisfy the American demand for Tom Baker stories. The Key to Time was then released as a special edition, numbered & limited to 15,000 with brand new extras in Region 2 on the 24th September 2007, which sold out very quickly with this set commanding a premium price on eBay for quite some time. The Key to Time Box Set was reissued in a non limited edition in November 2009 and can now be had for a very reasonable price.